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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The stress of moving out : physiological and behavioural effects of commercial transport on Atlantic salmon (Salmo salar) smolts

Nomura, Miki 05 1900 (has links)
Despite the controversy over environmental sustainability, salmon aquaculture in British Columbia is economically important for many coastal communities and is reported as being the largest agricultural export product for the province. This thesis examined the welfare status of commercially produced Atlantic salmon smolts during transport from freshwater farms to the saltwater net pens using physiology and behaviour to assess transport stress. Smolts were transported first by truck from the freshwater farm to the dock, and then in the flow-through cargo holds of a live-haul vessel to the saltwater net pens. Fish and water were sampled before and after truck transport, and several times aboard the vessel. Assessment of stress was based on measurement of plasma cortisol, glucose, lactate, potassium, sodium and chloride concentrations, as well as behavioural observations made on underwater video footage. Seven transports of fish originating from two different hatcheries were sampled; one was a land-based tank hatchery that required a 30-min drive to the dock, and the other a lake net pen facility that was 90 min to the dock. Analysis of plasma constituents supported previous studies that recovery from the stress accumulated during loading and truck transport can be quite rapid in a live-haul vessel. Underwater video footage, recorded at the freshwater farms and in the cargo holds of the Sterling Carrier, also suggested recovery onboard in that for the most part, behaviour onboard was similar to behaviour at the freshwater farms. There were some significant differences between fish from the two types of hatcheries, particularly in the original hatchery conditions and in their behavioural responses to transport conditions; however, post-transport growth and mortality rates reported by the saltwater farms showed no significant difference. Although fish were subjected to moderately stressful conditions during part of the process, smolt transport as currently carried out by our industry partners reflects good husbandry practices and fish welfare.
2

Acclimation of Holstein Calves to Transit Stress: The Integration of Endocrine, Immune, and Behavior Systems

Adams, Amber 2012 August 1900 (has links)
Little is known about the adaptation of livestock to repeated transport. This study determined how repeated transport affected calf feed intake, plasma cortisol (CORT), post-transport behavior, and the expression of immune-related genes. Thirty-six 4-month-old Holstein steer calves were housed in groups of six with each group randomly assigned to either transport (T) or control (C) treatments. The T calves were hauled for 6 h in a 7.3 m x 2.4 m goose-neck trailer, at an average density of 0.87 m2/calf, every 7 d for five consecutive weeks. Individual daily intake was determined using Calan gate feeders. Blood samples were obtained in the trailer or home pen via jugular venipuncture before loading, and after 2, 4, and 6 h of transport. Samples were analyzed for CORT, serotonin, tryptophan, and the gene expression of interleukin-4 (IL-4), interleukin-6 (IL-6), chemokine (C-X-C motif) receptor 2, interleukin-12, toll-like receptor-4, toll-like receptor-2, and 5-hydroxytryptamine receptor 2A in leukocytes. Behavior was recorded for transported calves at 5-min intervals for 1 h after return to their home pens. The C calves had a higher feed intake than T calves overall (P = 0.01), on the day of transport (P = 0.007), and the day after transport (P = 0.02). Pre-transport CORT concentrations did not differ by treatment (P = 0.77) or trial (P = 0.32). However, the T calves had higher response CORT concentrations than C calves during Transport 3 (P = 0.006), Transport 4 (P = 0.001) and Transport 5 (P = 0.02). The T calves had the highest response CORT concentrations after 2 h of transport and the lowest response CORT concentrations after 6 h of transport (P < 0.0001). Treatment did not affect gene expression in leukocytes, however, the expression of IL-4 (P = 0.01) and IL-6 (P = 0.05) was significantly lower after 2 h of transport than any other sampling times. These results suggest conflicting conclusions on whether the calves started to acclimate after being transported five times. However, CORT and gene expression differences occurred in response to the blood sampling regimen, which may provide insight to how calves acclimate during prolonged stress.
3

The stress of moving out : physiological and behavioural effects of commercial transport on Atlantic salmon (Salmo salar) smolts

Nomura, Miki 05 1900 (has links)
Despite the controversy over environmental sustainability, salmon aquaculture in British Columbia is economically important for many coastal communities and is reported as being the largest agricultural export product for the province. This thesis examined the welfare status of commercially produced Atlantic salmon smolts during transport from freshwater farms to the saltwater net pens using physiology and behaviour to assess transport stress. Smolts were transported first by truck from the freshwater farm to the dock, and then in the flow-through cargo holds of a live-haul vessel to the saltwater net pens. Fish and water were sampled before and after truck transport, and several times aboard the vessel. Assessment of stress was based on measurement of plasma cortisol, glucose, lactate, potassium, sodium and chloride concentrations, as well as behavioural observations made on underwater video footage. Seven transports of fish originating from two different hatcheries were sampled; one was a land-based tank hatchery that required a 30-min drive to the dock, and the other a lake net pen facility that was 90 min to the dock. Analysis of plasma constituents supported previous studies that recovery from the stress accumulated during loading and truck transport can be quite rapid in a live-haul vessel. Underwater video footage, recorded at the freshwater farms and in the cargo holds of the Sterling Carrier, also suggested recovery onboard in that for the most part, behaviour onboard was similar to behaviour at the freshwater farms. There were some significant differences between fish from the two types of hatcheries, particularly in the original hatchery conditions and in their behavioural responses to transport conditions; however, post-transport growth and mortality rates reported by the saltwater farms showed no significant difference. Although fish were subjected to moderately stressful conditions during part of the process, smolt transport as currently carried out by our industry partners reflects good husbandry practices and fish welfare.
4

The stress of moving out : physiological and behavioural effects of commercial transport on Atlantic salmon (Salmo salar) smolts

Nomura, Miki 05 1900 (has links)
Despite the controversy over environmental sustainability, salmon aquaculture in British Columbia is economically important for many coastal communities and is reported as being the largest agricultural export product for the province. This thesis examined the welfare status of commercially produced Atlantic salmon smolts during transport from freshwater farms to the saltwater net pens using physiology and behaviour to assess transport stress. Smolts were transported first by truck from the freshwater farm to the dock, and then in the flow-through cargo holds of a live-haul vessel to the saltwater net pens. Fish and water were sampled before and after truck transport, and several times aboard the vessel. Assessment of stress was based on measurement of plasma cortisol, glucose, lactate, potassium, sodium and chloride concentrations, as well as behavioural observations made on underwater video footage. Seven transports of fish originating from two different hatcheries were sampled; one was a land-based tank hatchery that required a 30-min drive to the dock, and the other a lake net pen facility that was 90 min to the dock. Analysis of plasma constituents supported previous studies that recovery from the stress accumulated during loading and truck transport can be quite rapid in a live-haul vessel. Underwater video footage, recorded at the freshwater farms and in the cargo holds of the Sterling Carrier, also suggested recovery onboard in that for the most part, behaviour onboard was similar to behaviour at the freshwater farms. There were some significant differences between fish from the two types of hatcheries, particularly in the original hatchery conditions and in their behavioural responses to transport conditions; however, post-transport growth and mortality rates reported by the saltwater farms showed no significant difference. Although fish were subjected to moderately stressful conditions during part of the process, smolt transport as currently carried out by our industry partners reflects good husbandry practices and fish welfare. / Land and Food Systems, Faculty of / Graduate
5

ROLE OF DIETARY INTERVENTIONS IN REDUCING THE NEGATIVE IMPACT OF STRESSFUL EVENTS IN THE PIG

Candace Moriah Young (13171671) 29 July 2022 (has links)
<p>Two experimentswere  conducted  using  pigs  at different  life stages to  determine  the  effects  of dietary  tryptophan  and  water  delivered  oregano  essential  oil  on growth performance, rectal temperature, water use,intestinal integrity and gene expression of biomarkers in the face heat or transport stress. In the first experiment, 192 grow-finish pigs were used to investigate the effects of  water  supplementation  of  oregano  essential  oil  (OEO)  on  growth  performance,  water  intake, rectal temperature, intestinal integrity, and expression of genetic biomarkers during an acute heat challenge. Pigs were randomly allotted to 2 X 2 factorial arrangement of treatments with pigs being heat  stressed  or  not  and  being  supplemented  with  OEO  or  not with 8  replicate  pens  of  each treatment  with  6  pigs/pen  (4  barrows,  2  gilts  per  pen).  Water  treatments  were administered immediately, with  dosing at  47 μL/L of OEO. One-half  of  the  pigs  on  each  water  treatment remained under thermoneutral conditions (TN; 21.1C), while the other half was subjected to a 3 d diurnal, acute heat stress (HS) with 12 hours at 33.3 oC (7AM-7PM) and 12 hours at 26.7oC (7PM-7AM). Three days post-HS, temperatures were reduced back to TN for the rest of the study, and pigs remained on their water treatments. Rectal temperatures were collected in the morning and evening  of  the  heat  stress  period  on  one  barrow  and  one  gilt  in  each  pen. Jejunal  tissue was collected for subsequent histological examination and determination of gene expression. All data were  analyzed  using  the  GLM  procedure  of  SAS  (ver.  9.4).  Pigs  subjected  to  heat  stress  had reduced ADG (P < 0.003) and G:F (P < 0.008) during the 3d heat stress compared to pigs reared under thermoneutral conditions. However, post-heatstress, heat stressed pigs had compensatory gain resulting in increased ADG (P < 0.001) and G:F (P < 0.001) compared to thermoneutral reared pigs.   Overall,  there  was an  interaction  (P  <  0.006)  observed  between  water  and  heat  treatment with  OEO  increasing  ADG  in  thermoneutral  pigs  but  not  in  heat  stressed  pigs.  Similarly, interactions  between  water  and  heat  treatment  were  observed  for  ADFI  during  heat  stress  (P  < 0.004),  post  heat  stress  (P  <  0.01),  and  overall  (P  <  0.004)  from  increasing  OEO  intake  in thermoneutral pigs but not in heat stressed pigs. Rectal temperatures were higher (P < 0.001) for heat stressed pigs at the end of d 1 and 2 of the acute heat challenge compared to TN housed pigs. Pigs exposed to HS also used more water than pigs housed in a thermoneutral environment (P < 0.002). There were no differences between villi height, crypt depth or VH:CD between treatment groups  (P  >0.05).  There  was  also  no  difference  in  TP53  and  CDKNA1  gene  expression  among treatments (P > 0.10). In the second experiment, 36 barrows were used in an 18d experiment to investigate the effects of pre-weaning tryptophan supplementation on performance and intestinal integrity following  weaning  with  or  without  transport  stress  at  weaning.  Pigs  were  randomly allotted to 2 X 2 factorial arrangement of treatments of pre-weaning tryptophan supplementation or not and weaning transport or not. Pigs on the tryptophan treatment received 0.35, 0.45, and 0.55 g Trp/d in 5 day intervals, beginning 15 d prior to weaning.Tryptophan was dissolved in chocolate milk and administered by oral gavage with control pigs receiving milk only. At weaning, 4 pigs from each pre-weaning treatmentwere euthanized for collection of jejunal tissue.  Of the remaining pigs, half the pigs oneach treatment were transported for 12 h, and half were moved into individual pens  with  no  transport.  Following  transport,  all  pigs  were  individually  housed  and  provided  ad libitum  access  towater  andfeed  from  a  common  diet.  On  d  3  post-weaning,  all  pigswere euthanized for collection of jejunal tissue. Jejunal tissue was used for histological examination and for determination of gene expression. All data were analyzed using the GLM procedure of SAS (9.4).  No  effects  of  Trp  supplementation  were  observed  on  pre-weaning  (P  >  0.10)  growth. Pig BW and ADFI were unaffected (P > 0.10) by Trp supplementation and transport at weaning. Post-weaning, there was a tendency (P < 0.06) for an effect of transport on ADG as transported pigs lost weight in the 3 d post-weaning period while non-transported pigs gained slightly. Gain:Feed post-weaning  was  lower  (P  <  0.04)  for  transported  pigs  compared  to  non-transported  pigs.  No differences  were  observed  for villus base  and  mid  width,  villus  height,  crypt  depth  or  villus height:crypt   depth.   There   was   a   tendency   for   an   interaction   of   transportation   and   Trp supplementation  (P  <  0.06)  on  villi  base  width  driven  by  an  increased  villus  width  in  non-transported pigs given supplemental Trp but a decrease in villus width in transported pigs given supplemental Trp.These results conclude that these alleviating agents had minimal effects when pigs  were  stressed, however TN grow-finish pigs  benefitted  from  OEO  water  supplementation among growth performance.</p>
6

Óleo essencial de Lippia alba como anestésico e antibacteriano para peixes / Essential oil of Lippia alba as anaesthetic and antibacterial for fish

Cunha, Mauro Alves da 14 January 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / There are some effective anesthetics and antibacterial for fishes, but it is important to search new alternatives of substances easily obtained, of low cost for fish farmers and with no risk to fish and human health. Therefore, this study analyzed the use of essential oil (EO) of Lippia alba as anesthetics, in silver catfish (Rhamdia quelen) and slender seahorse (Hippocampus reidi).To identify time of induction and anesthesia recovery, the fishes were placed in aquaria containing different concentrations of EO and after induction, fish were transferred to anesthetic-free aquaria to evaluate recovery time. Blood collect of the fish for analysis of plasma cortisol (silver catfish) and Blood glucose levels (seahorse). In silver catfish blood was collected 0, 1 and 4 h after anesthesia and air exposure and some epecimens were killed at time 0h for sensorial evaluation of the fillet. In slender seahorses blood was collected begin and after the transport of the 4 our 24 h. The results obtained showed that the EO could be used at concentrations ranging from 100 to 500 mg L−1 to induce anesthesia (stage 4) in silver catfish, as it reduces plasma cortisol when the fish is exposed to air, and does not modify the odor and the flavor of the fillet. In seahorses this EO is effective to induce slight sedation in slender seahorse at 10-20 μL L-1and deep anesthesia at 50 450 μL L-1. Furthermore, 15 μL L-1 of EO in the water of transport inhibits elevation of blood glucose and neutrophils and lymphocytes decrease in slender seahorse, and therefore its use in the transport of this species is suggested. / Existem alguns anestésicos e antibacterianos efetivos para peixes, mas é importante buscar novas alternativas de substâncias de fácil aquisição e baixo custo aos piscicultores e que não ofereçam aos animais e manipuladores riscos à saúde. Portanto, este trabalho verificou a utilização do óleo essencial de Lippia alba (OE) como anestésico em jundiás (Rhamdia quelen) e em cavalos marinhos (Hippocampus reidi). Para identificar o tempo de indução e recuperação anestésica os peixes foram colocados em aquários com 1 L de água contendo diferentes concentrações do OE, e após a indução, foram transferidos para aquários livres do OE para avaliar o tempo de recuperação. Foi realizada coleta de sangue dos peixes para análise de cortisol plasmático (jundiá) e glicose sanguínea (cavalo marinho). Em jundiás o sangue foi coletado 0, 1 e 4 h após anestesia e exposição ao ar e alguns exemplares do tempo 0 h foram abatidos para testes de avaliação sensorial do filé. Nos cavalos marinhos o sangue foi coletado antes e após transporte realizado por 4 ou 24 horas. Os resultados obtidos mostraram que o OE é uma alternativa segura como anestésico para o jundiá na concentração de 100 a 500 mg L−1, pois reduz o cortisol plasmático no momento da exposição ao ar e não deixa odor ou sabor desagradável ao filé. Em cavalos marinhos este OE mostrou-se efetivo para sedação (10-20 μL L-1) e para anestesia profunda (50 450 μL L-1). Além disso, 15 μL L-1 do OE na água do transporte inibe a elevação da glicose sanguínea e conseqüentemente seu uso no transporte desta espécie é sugerido.
7

Stress Effects on Solute Transport in Fractured rocks

Zhao, Zhihong January 2011 (has links)
The effect of in-situ or redistributed stress on solute transport in fractured rocks is one of the major concerns for many subsurface engineering problems. However, it remains poorly understood due to the difficulties in experiments and numerical modeling. The main aim of this thesis is to systematically investigate the influences of stress on solute transport in fractured rocks, at scales of single fractures and fracture networks, respectively. For a single fracture embedded in a porous rock matrix, a closed-form solution was derived for modeling the coupled stress-flow-transport processes without considering damage on the fracture surfaces. Afterwards, a retardation coefficient model was developed to consider the influences of damage of the fracture surfaces during shear processes on the solute sorption. Integrated with particle mechanics models, a numerical procedure was proposed to investigate the effects of gouge generation and microcrack development in the damaged zones of fracture on the solute retardation in single fractures. The results show that fracture aperture changes have a significant influence on the solute concentration distribution and residence time. Under compression, the decreasing matrix porosity can slightly increase the solute concentration. The shear process can increase the solute retardation coefficient by offering more sorption surfaces in the fracture due to gouge generation, microcracking and gouge crushing. To study the stress effects on solute transport in fracture systems, a hybrid approach combing the discrete element method for stress-flow simulations and a particle tracking algorithm for solute transport was developed for two-dimensional irregular discrete fracture network models. Advection, hydrodynamic dispersion and matrix diffusion in single fractures were considered. The particle migration paths were tracked first by following the flowing fluid (advection), and then the hydrodynamic dispersion and matrix diffusion were considered using statistic methods. The numerical results show an important impact of stress on the solute transport, by changing the solute residence time, distribution and travel paths. The equivalent dispersion coefficient is scale dependent in an asymptotic or exponential form without stress applied or under isotropic compression conditions. Matrix diffusion plays a dominant role in solute transport when the hydraulic gradient is small. Outstanding issues and main scientific achievements are also discussed. / QC 20111011

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